'\" te
.\"  Copyright 1989 AT&T
.\" Copyright (C) 2004, Sun Microsystems, Inc. All Rights Reserved
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.TH YPBIND 8 "May 13, 2017"
.SH NAME
ypbind \- NIS binder process
.SH SYNOPSIS
.LP
.nf
\fB/usr/lib/netsvc/yp/ypbind\fR [\fB-broadcast\fR | \fB-ypset\fR | \fB-ypsetme\fR]
.fi

.SH DESCRIPTION
.LP
NIS provides a simple network lookup service consisting of databases and
processes. The databases are stored at the machine that runs an NIS server
process. The programmatic interface to NIS is described in \fBypclnt\fR(3NSL).
Administrative tools are described in \fBypinit\fR(8), \fBypwhich\fR(1), and
\fBypset\fR(8). Tools to see the contents of NIS maps are described in
\fBypcat\fR(1), and \fBypmatch\fR(1).
.sp
.LP
\fBypbind\fR is a daemon process that is activated at system startup time from
the \fBsvc:/network/nis/client:default\fR service. By default, it is invoked as
\fBypbind\fR \fB-broadcast\fR. \fBypbind\fR runs on all client machines that
are set up to use \fBNIS\fR. The function of
\fBypbind\fR is to remember information that lets all \fBNIS\fR client
processes on a node communicate with some \fBNIS\fR server process.
\fBypbind\fR must run on every machine which has \fBNIS\fR client processes.
The \fBNIS\fR server may or may not be running on the same node, but must be
running somewhere on the network.
.sp
.LP
The information \fBypbind\fR remembers is called a \fIbinding\fR \(em the
association of a domain name with a \fBNIS\fR server. The process of binding is
driven by client requests.  As a request for an unbound domain comes in, if
started with the \fB-broadcast\fR option, the \fBypbind\fR process broadcasts
on the net trying to find an \fBNIS\fR server, a \fBypserv\fR process
serving the domain. Since the binding is established by broadcasting, there
must be at least one \fBNIS\fR server on the net. If started without the
\fB-broadcast\fR option, \fBypbind\fR process steps through the list of
\fBNIS\fR servers that was created by \fBypinit\fR \fB-c\fR for the requested
domain. There must be an \fBNIS\fR server process on at least one of the hosts
in the \fBNIS\fR servers file. It is recommended that you list each of these
NIS servers by name and numeric IP address in \fB/etc/hosts\fR. Though the
practice is not recommended, NIS allows you to list servers by numeric address
only, bypassing \fB/etc/hosts\fR. In such a configuration, \fBypwhich\fR(1)
returns a numeric address instead of a name.
.sp
.LP
Once a domain is bound by \fBypbind\fR, that same binding is given to every
client process on the node. The \fBypbind\fR process on the local node or a
remote node may be queried for the binding of a particular domain by using the
\fBypwhich\fR(1) command.
.sp
.LP
If \fBypbind\fR is unable to speak to the \fBNIS\fR server process it is bound
to, it marks the domain as unbound, tells the client process that the domain is
unbound, and tries to bind the domain once again. Requests received for an
unbound domain will wait until the requested domain is bound. In general, a
bound domain is marked as unbound when the node running the \fBNIS\fR server
crashes or gets overloaded. In such a case, \fBypbind\fR will try to bind to
another \fBNIS\fR server using the process described above.\fBypbind\fR also
accepts requests to set its binding for a particular domain.  The request is
usually generated by the \fBypset\fR(8) command. In order for \fBypset\fR to
work, \fBypbind\fR must have been invoked with flags \fB-ypset\fR or
\fB-ypsetme\fR.
.SH OPTIONS
.ne 2
.na
\fB\fB-broadcast\fR\fR
.ad
.sp .6
.RS 4n
Send a broadcast datagram using \fBUDP/IP\fR that requests the information
needed to bind to a specific \fBNIS\fR server. This option is analogous to
\fBypbind\fR with no options in earlier Sun releases and is recommended for
ease of use.
.RE

.sp
.ne 2
.na
\fB\fB-ypset\fR\fR
.ad
.sp .6
.RS 4n
Allow users from any remote machine to change the binding by means of the
\fBypset\fR command. By default, no one can change the binding. This option is
insecure.
.RE

.sp
.ne 2
.na
\fB\fB-ypsetme\fR\fR
.ad
.sp .6
.RS 4n
Only allow \fBroot\fR on the local machine to change the binding to a desired
server by means of the \fBypset\fR command.  \fBypbind\fR can verify the caller
is indeed a \fBroot\fR user by accepting such requests only on the loopback
transport. By default, no external process can change the binding.
.RE

.SH FILES
.ne 2
.na
\fB\fB/var/yp/binding/\fIypdomain\fR/ypservers\fR\fR
.ad
.sp .6
.RS 4n
Lists the servers to which the NIS client is allowed to bind.
.RE

.sp
.ne 2
.na
\fB\fB/etc/inet/hosts\fR\fR
.ad
.sp .6
.RS 4n
File in which it is recommended that NIS servers be listed.
.RE

.SH SEE ALSO
.LP
.BR svcs (1),
.BR ypcat (1),
.BR ypmatch (1),
.BR ypwhich (1),
.BR ypclnt (3NSL),
.BR hosts (5),
.BR ypfiles (5),
.BR attributes (7),
.BR smf (7),
.BR ifconfig (8),
.BR svcadm (8),
.BR ypinit (8),
.BR ypset (8)
.SH NOTES
.LP
\fBypbind\fR supports multiple domains. The \fBypbind\fR process can maintain
bindings to several domains and their servers, the default domain is the one
specified by the \fBdomainname\fR(8) command at startup time.
.sp
.LP
The \fB-broadcast\fR option works only on the \fBUDP\fR transport. It is
insecure since it trusts "any" machine on the net that responds to the
broadcast request and poses itself as an \fBNIS\fR server.
.sp
.LP
The \fBypbind\fR service is managed by the service management facility,
\fBsmf\fR(7), under the service identifier:
.sp
.in +2
.nf
svc:/network/nis/client:default
.fi
.in -2
.sp

.sp
.LP
Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using \fBsvcadm\fR(8). The service's
status can be queried using the \fBsvcs\fR(1) command.
